ABSTRACT We studied the fungal endophyte community of the leaves of Myracrodruon urundeuva in Brazil along with their potential to produce L-asparaginase. In total, 187 endophytes were isolated. The colonization rate of leaf fragments from caatinga (10.41 %) was lower than those from brejo de altitude (39.58 %). Sequences of ITS rDNA from all endophytes revealed relationships with Ascomycota (Botryosphaeriales, Chaetothyriales, Diaporthales, Eurotiales, Glomerellales, Hypocreales, and Pleosporales) and Basidiomycota (Polyporales). The most frequent endophytes were members of the genus Diaporthe. Talaromyces was an indicator genus for caatinga while Phyllosticta, Diaporthe, and Colletotrichum were for brejo de altitude. The composition of endophytic fungi in caatinga and brejo de altitude differed significantly, its richness and diversity (H' = 3.41) being significantly higher in brejo de altitude. Diaporthe sp. URM 7793 was the best producer of L-asparaginase (2.41 U/g), followed by Diaporthe sp. URM 7779 (2.00 U/g), Talaromyces sp. URM 7785 (1.91 U/g), and Diaporthe sp. URM 7792 (1.47 U/g). The composition of endophytic fungi assemblages is strongly influenced by the type of ecosystem. In its natural habitat, M. urundeuva harbors an important diversity of endophytes, which could be used to produce L-asparaginase.

O objetivo deste trabalho foi o de determinar a infectividade, a riqueza de FMA e a condição micorrízica da vegetação em área de Caatinga não antropizada. Coleta de solo e raízes foi realizada em Triunfo/PE. Raízes foram examinadas para determinação da colonização micorrízica. O número mais provável (NMP) de propágulos infectivos de FMA foi estimado por diluições sucessivas do solo e a utilização de milho (Zea mays L.) como planta isca. Glomerosporos foram quantificados e preparados em lâminas, para identificação das espécies. As plantas apresentaram-se pouco colonizadas (média < 10%) e o número de glomerosporos foi baixo (< 1 glomerosporo g-1 de solo), como registrado em outras áreas de Caatinga. O NMP de propágulos de FMA variou entre 64 e 70 cm-3 solo, indicando a importância dos outros propágulos (além dos glomerosporos) na dispersão dos FMA. Foram registrados 16 táxons de FMA, dos gêneros Acaulospora, Entrophospora, Gigaspora, Glomus, Kuklospora, Pacispora e Paraglomus; Glomus foi o mais representativo (sete espécies). Pacispora boliviana está sendo relatada pela primeira vez no Brasil. Os elevados teores de P na área provavelmente contribuiram para os baixos valores de colonização, infectividade e riqueza de FMA na área estudada. Confirma-se que os FMA são comuns em solos do semiárido brasileiro, com espécies de Glomus predominando nesse ambiente.

The objective of this work was to determine the infectivity and richness of AMF and the mycorrhizal conditions of the vegetation in a preserved area of Caatinga. Soil and root samples were taken in two subareas in the municipality of Triunfo, PE. The roots were stained with Trypan blue, and observed with a microscope to determine if colonization of mycorrhizal fungi was present. Glomerospores were extracted from soil, counted, mounted on microscope slides and the AMF species were identified. The plants from the area showed < 10% colonization. The number of glomerospores (<1 g-1 soil) did not differ between the subareas although in one area the amount of P in the soil was three times higher than in the other. The number of AMF propagules varied from 64 to 70 cm-3 in the soil. Sixteen taxa of AMF were registered and Glomus was the most representative genus, with seven species. Pacispora boliviana is reported for the first time in Brazil. The high amount of P probably contributes to the low values of propagules, colonization, infectivity and richness of AMF in the area. AMF have been commonly found in the Brazilian semiarid region and species of Glomus are predominant in this environment.